| Method in an integrated circuit (ic) manufacturing process for identifying and redirecting ics mis-processed during their manufacture -> Monitor Keywords |
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Method in an integrated circuit (ic) manufacturing process for identifying and redirecting ics mis-processed during their manufactureRelated Patent Categories: Data Processing: Design And Analysis Of Circuit Or Semiconductor Mask, Circuit Design, Programmable Integrated Circuit (e.g., Basic Cell, Standard Cell, Macrocell)Method in an integrated circuit (ic) manufacturing process for identifying and redirecting ics mis-processed during their manufacture description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070094632, Method in an integrated circuit (ic) manufacturing process for identifying and redirecting ics mis-processed during their manufacture. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of application Ser. No. 11/150,752, filed Jun. 10, 2005, which will issue as U.S. Pat. No. 7,124,050, on Oct. 17, 2006, which is a continuation of application Ser. No. 10/600,148, filed Jun. 19, 2003, now U.S. Pat. No. 6,944,567, issued Sep. 13, 2005, which is a continuation of application Ser. No. 10/067,728, filed Feb. 4, 2002, now U.S. Pat. No. 6,594,611, issued Jul. 15, 2003, which is a continuation of application Ser. No. 09/793,938, filed Feb. 27, 2001, now U.S. Pat. No. 6,363,329, issued Mar. 26, 2002, which is a continuation of application Ser. No. 09/537,839, filed Mar. 29, 2000, now U.S. Pat. No. 6,208,947, issued Mar. 27, 2001, which is a continuation of application Ser. No. 09/302,338, filed Apr. 29, 1999, now U.S. Pat. No. 6,067,507, issued May 23, 2000, which is a continuation of application Ser. No. 08/806,442, filed Feb. 26, 1997, now U.S. Pat. No. 5,915,231, issued Jun. 22, 1999, which is related to: co-pending Ser. No. 08/591,238, filed Jan. 17, 1996, now abandoned; Ser. No. 08/664,109, filed Jun. 13, 1996, now U.S. Pat. No. 5,895,962, issued Apr. 20, 1999; and Ser. No. 08/785,353, filed Jan. 17, 1997 now U.S. Pat. No. 5,927,512, issued Jul. 27, 1999. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates in general to integrated circuit (IC) manufacturing and, more specifically, to methods in IC manufacturing processes for identifying and redirecting ICs mis-processed during their manufacture. [0004] 2. State of the Art [0005] As shown in FIG. 1, a typical process 10 for manufacturing very small electronic circuits referred to as "Integrated Circuits" (ICs) begins with the ICs being formed or "fabricated" on the surface of a wafer 12 of semiconductor material, such as silicon. Once fabricated, ICs are electronically probed to determine whether they are functional (i.e., "good") or nonfunctional (i.e., "bad"), and a computer then stores an electronic wafer map 14 of the wafer 12 identifying the locations of the good and bad ICs on the wafer 12. [0006] After being probed, ICs are sawed from their wafer 12 into discrete IC dice or "chips" using high-speed precision dicing equipment. IC dice identified as good by their wafer map 14 are then each "picked" by automated equipment from their sawed wafer 12 and "placed" on an epoxy coated bonding site of a lead frame, while IC dice identified as bad are discarded into a scrap bin 16. The epoxy attaching the good IC dice to their lead frames is then allowed to cure, and the attached dice are wire bonded to their lead frames using high speed bonding equipment. At this point in the process 10, the lead frames of IC dice are still connected to other lead frames. [0007] Once wire bonded, IC dice and their lead frames are formed into IC packages using a hot thermosetting plastic encapsulant injected into a mold. Leads of the lead frames project from the IC packages after encapsulation, and these leads are dipped in a cleansing chemical bath in a process referred to as "de-flash." After de-flash, IC packages are cured to set their plastic encapsulant, and their projecting leads are then electroplated with a lead/tin finish. [0008] After lead finishing, connections between the lead frames of different IC packages are cut to "singulate" the IC packages into discrete IC devices. Discrete devices are then tested in a simple electronic test that checks for "opens" (i.e., no connection) within the devices where connections should exist and "shorts" (i.e., a connection) where connections should not exist. Devices that fail the opens/shorts test are discarded into the scrap bin 16, and devices that pass proceed to extensive back-end test procedures where they are tested for functionality and operability before being shipped to customers. [0009] On occasion, bad IC dice are accidentally picked from a sawed wafer 12 for subsequent assembly and back-end testing as described above. This can happen, for example, because a human, software, or electronic error causes the automated pick and place equipment described above to access the wrong wafer map 14 for a wafer 12. It can also happen because of a misalignment, referred to as a "registration" error, between the automated pick and place equipment and a wafer 12. In either case, such accidents typically are not detected until the bad IC dice undergo at least some back-end testing and, as a result, waste back-end testing resources. Therefore, there is a need in the art for a method of identifying and discarding accidentally assembled IC dice before the dice undergo back-end testing procedures. [0010] As described in U.S. Pat. Nos. 5,301,143, 5,294,812, and 5,103,166, some methods have been devised to electronically identify IC dice. Such methods take place "off" the manufacturing line, and involve the use of electrically retrievable identification (ID) codes, such as so-called "fuse IDs," programmed into individual IC dice to identify the dice. The programming of a fuse ID typically involves selectively blowing an arrangement of fuses or anti-fuses in an IC die so that when the fuses or anti-fuses are accessed, they output a selected ID code. Unfortunately, none of these methods addresses the problem of identifying and discarding accidentally assembled IC dice "on" a manufacturing line. BRIEF SUMMARY OF THE INVENTION [0011] The present invention provides a method that can identify and discard accidentally assembled integrated circuit (IC) dice "on" an IC manufacturing line before the dice undergo back-end testing procedures. [0012] In one embodiment, the method identifies and redirects ICs that have been mis-processed, such as bad ICs identified at probe that have accidentally been assembled and packaged. The method includes storing data, such as an electronic wafer map, at probe, for example, in association with a unique identification (ID) code, such as a fuse ID, of each of the ICs. The stored data indicates a process flow within the IC manufacturing process that each of the ICs should undergo. For example, the stored data may indicate that an IC is bad and should be discarded, or that an IC is good and should be assembled and packaged. [0013] As described above, on occasion, one or more ICs do not undergo the process flow they should undergo. For example, some bad ICs may proceed through assembly and packaging rather than being discarded. To check for ICs that have not undergone the process flow they should undergo, the present method also includes reading the ID code of each of the ICs at, for example, the opens/shorts test at the end of assembly. The data (e.g., the wafer map) stored in association with the ID code of each of the ICs is then accessed and evaluated to identify any ICs that have undergone a process flow within the IC manufacturing process that is different from the process flow their data indicates they should have undergone, such as bad ICs that have proceeded through assembly and packaging. Any ICs identified as having been mis-processed are then redirected within the IC manufacturing process. Thus, for example, bad ICs that have been assembled and packaged may be discarded so they do not proceed to back-end testing. [0014] In another embodiment of the present invention, a method of manufacturing IC devices, such as Dynamic Random Access Memory Devices (DRAMs), from semiconductor wafers includes providing the semiconductor wafers and fabricating ICs on the wafers. A substantially unique ID code, such as a fuse ID, is then stored in each of the ICs, and data is stored in association with the ID code of each of the ICs that indicates a manufacturing process flow that each of the ICs should undergo. Each IC is then separated from its wafer to form an IC die, and the IC dice are assembled into IC devices, such as wire bond/lead frame devices, Chip On Board (COB) devices, or flip-chip devices. The ID code associated with each of the IC devices is then read, and the data stored in association with the ID code associated with each of the IC devices is accessed and evaluated to identify any IC devices that have undergone a manufacturing process flow that is different from the manufacturing process flow their data indicates they should have undergone. These identified IC devices are then redirected (e.g., discarded), and the remaining IC devices continue on to back-end testing. [0015] A further embodiment of the present invention comprises a method of manufacturing Multi-Chip Modules (MCMs) similar to the method of manufacturing IC devices described above. [0016] A still further embodiment of the present invention comprises another method of manufacturing IC devices from semiconductor wafers. The method includes providing the semiconductor wafers and fabricating ICs on the wafers. Each IC is electronically probed to identify good and bad ICs on the wafers and then programmed with a unique fuse ID. An electronic wafer map is stored for each wafer indicating the locations of good and bad ICs on the wafer and associating each IC on the wafer with its fuse ID. Each IC is then sawed from its wafer to form a discrete IC die that is automatically picked and placed on an epoxy coated bonding site of a lead frame. The epoxy is allowed to cure, and the IC dice are then wire bonded to their respective lead frames. Next, the IC dice and their associated lead frames are injection molded to form IC packages. Projecting leads of the packages are then de-flashed, the packages are cured, and the leads are then electroplated. Then, each package is singulated to form a discrete IC device, and each device is tested for opens and shorts. The fuse ID associated with each IC device is then electrically retrieved so the wafer map stored in association with the fuse ID associated with each of the IC devices may be accessed and evaluated to identify any IC devices that include a bad IC and any IC devices that include a good IC. Any IC devices identified as including a bad IC are discarded, and any IC devices identified as including a good IC proceed to back-end testing. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0017] FIG. 1 is a flow diagram illustrating a conventional integrated circuit (IC) manufacturing process; and [0018] FIG. 2 is a flow diagram illustrating an IC manufacturing process in which accidentally assembled IC dice are identified and discarded in accordance with the present invention before back-end testing. DETAILED DESCRIPTION OF THE INVENTION [0019] As shown in FIG. 2, an inventive method 20 for manufacturing integrated circuits (ICs) from a group of semiconductor wafers 22 includes the step 24 of fabricating the ICs on the wafers 22. It will be understood by those having skill in the field of this invention that the present invention is applicable to any IC devices, including Dynamic Random Access Memory (DRAM) ICs, Static Random Access Memory (SRAM) ICs, Synchronous DRAM (SDRAM) ICs, processor ICs, Single In-line Memory Modules (SIMMs), Dual In-line Memory Modules (DIMMs), and other Multi-Chip Modules (MCMs). It will also be understood that although the present invention will be described below in the context of a wire bond/lead frame assembly process, the present invention is applicable to any IC assembly process, including, for example, Chip On Board (COB), flip chip, and Tape-Automated Bonding (TAB) processes. Continue reading about Method in an integrated circuit (ic) manufacturing process for identifying and redirecting ics mis-processed during their manufacture... Full patent description for Method in an integrated circuit (ic) manufacturing process for identifying and redirecting ics mis-processed during their manufacture Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method in an integrated circuit (ic) manufacturing process for identifying and redirecting ics mis-processed during their manufacture patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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